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NJHTools

Image Compressor

Compress JPEG, PNG, and WebP images instantly and reduce file size in KB — adjust quality, see the savings, and download. Every image is processed in your browser, nothing is uploaded.

Need to change the width and height instead? Use the Image Resizer →

Output Format
80%

Lower quality means smaller files.

Leave empty to keep original size.

Drag images here, or click to upload

All processing happens in your browser — nothing is uploaded to a server.

How to compress images

  1. Drag your images onto the drop zone, or click it to select files — JPEG, PNG, and WebP are all supported, and you can add several at once.
  2. Choose an output format and adjust the quality slider — lower quality produces smaller files for JPEG and WebP.
  3. Optionally set a max width to resize large images while keeping their aspect ratio.
  4. Compare the before/after previews and file-size savings, then click Download on a single image or Download All.

Every image is decoded, resized, and re-encoded entirely in your browser with the Canvas API — no file is ever uploaded, tracked, or stored.

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Frequently Asked Questions

Is this image compressor free?↓

Yes, it is completely free with no signup or account required, and there is no watermark added to your images.

Are my images uploaded to a server?↓

No. Every image is decoded, resized, and re-encoded entirely in your browser using the Canvas API. Your files never leave your device and are never uploaded, tracked, or stored.

What image formats are supported?↓

You can upload JPEG, PNG, and WebP images, and export to any of those three formats. This lets you both compress and convert between formats in one step.

How does the quality slider affect file size?↓

For JPEG and WebP, lowering the quality applies stronger lossy compression, which reduces file size at the cost of some visual detail. PNG is a lossless format, so the quality slider has no effect for PNG output.

Can I compress multiple images at once?↓

Yes. You can upload several images at once, and the same format, quality, and max-width settings are applied to all of them. Use Download All to save the whole batch.

How do I reduce an image's size in KB?↓

Choose JPEG or WebP output and lower the quality slider — around 70–80% usually cuts file size substantially with little visible loss. The compressed size and percentage saved are shown for each image. If you also need different pixel dimensions, use the Image Resizer at www.njhouse.kr/tools/image-resizer.

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